Electroplating sludge drying treatment solutions

The treatment of electroplating wastewater uses many reducing agents, so the composition of Electroplating sludge is very complex, and Electroplating sludge contains a large amount of zinc, iron, copper, nickel and other toxic heavy metals, and the content of toxic heavy metals varies depending on the electroplating operation process. In the resourceful treatment of Electroplating sludge, it is necessary to pay attention to its sludge treatment harmless requirements and reduce its harmful effects on the environment, etc.

I. Resourceful treatment of electroplating sludge

One of the research hotspots of resource utilization technology is to find the resource recovery method of Electroplating sludge with simple operation, low cost and good effect. Common resource utilization technologies include wet extraction, thermal extraction and manufacturing of building materials.

II. Reduction of electroplating sludge

Electroplating sludge is the source electroplating wastewater, and there are three main approaches to achieve the reduction of Electroplating sludge as the generator of Electroplating sludge:

1. Adopt more advanced and environmentally friendly plating processes to achieve plating wastewater reduction or maximize the use of metals in plating wastewater.

2. To realize the diversion of electroplating wastewater, the wastewater generated from different electroplating processes (copper plating, nickel plating, zinc plating, etc.) needs to be stored and treated separately, which can enhance the taste of metals in Electroplating sludge and increase the added value on the one hand; and reduce the difficulty of Electroplating sludge treatment on the other hand.

3. Adopting energy-saving and emission reduction technology to achieve lower water content of the ex-factory Electroplating sludge, reduce the total amount of Electroplating sludge, and reduce the storage and transportation risks of Electroplating sludge and the disposal pressure of downstream hazardous waste disposal enterprises.

   
   

The drying treatment of Electroplating sludge mainly uses sludge dryers to dry Electroplating sludge with a moisture content of about 75% to a moisture content of about 10% (full drying) or to a moisture content of about 40% (semi-drying), so as to achieve the requirements of reduction and the next step of smelting and extraction of iron, copper, zinc and other metals in it.

Electroplating sludge drying has the following characteristics and requirements: the material is sticky and the liquidity is poor; the moisture content is high, the drying speed is slow and the energy consumption is high; the exhaust gas has an odor and needs to be treated; the material is heated evenly and the operating environment is good, and the index requirements are reached at one time. Electroplating sludge is quantitatively and continuously fed into the dryer filling port by the shaftless screw conveyor. After the material enters the paddle, the material is turned and stirred by the rotation of the paddle, which constantly changes the heating interface and contacts with the BODy and the paddle, and is fully heated so that the surface moisture contained in the material evaporates. At the same time, the material with the rotation of the paddle shaft into a spiral track to the direction of the discharge, in the transport continue to stir, so that the moisture seeping out of the material continue to evaporate. Then, the dried and evenly qualified products are discharged from the discharge port. The gas containing water vapor and a small amount of ultra-fine solid particles is sent to the water film spray washing tower, and the filtered gas is sent to the wastewater treatment unit after water-cooled settling. The remaining solid materials can be directly transported out to landfill.